An airline passenger removes his watch before being screened at a security checkpoint.
(REUTERS/Mike Segar)

Airport security screeners at Minneapolis-St. Paul International Airport reportedly failed 95 percent of security tests conducted earlier this month – an alarming finding at one of the nation’s busiest airports.

Agents from the Department of Homeland Security's Office of the Inspector General regularly pose as travelers and attempt to bring prohibited items such as weapons, explosives or drugs into the secure areas of American airports. The covert group, known as the “Red Team,” tried their luck at the Minneapolis airport, smuggling various contraband through security.

The team reportedly breached security successfully 17 out of 18 times.

Similar tests are reportedly conducted at airports across the country – but the findings normally are not made public. The results at Minneapolis-St. Paul Airport were leaked late last week.

"The tests are designed to drive improvements in screening procedures and employee performance,” a TSA spokesman told Fox News. “What is important to remember is that checkpoint tests represent but one element of a security process that includes both seen and unseen measures that begin when the reservation is made and concludes at destination arrival.”

The poor performance in Minneapolis harkens back to April 2016 when sources told Fox 9 that the same airport failed 9 out of 12 tests.

A year earlier, Melvin Carraway, the acting administrator for the Transportation Security Administration, was removed from his post following the revelation that across the country, TSA agents failed to detect more than 95 percent of potential threats during tests carried out by undercover agents.

“Red Team testing of the aviation security network has been part of TSA's mission advancement [since 2002],” then-Secretary of Homeland Security Jeh Johnson wrote in a statement responding to the reports of massive security failures back in 2015.

In addition to reassigning Carraway, Johnson promised more random testing, ordered additional training for TSA officers and directed TSA administration to “immediately revise its standard operating procedures for screening to address the specific vulnerabilities identified by the Inspector General’s testing.”

Each year, the TSA releases a review of the previous year, revealing how many firearms were discovered during TSA screenings in airports across the U.S.

Of the 738,318,264 passengers screened by TSA officers in 2016, there were 3,391 firearms found in carry-on bags at checkpoints. Of those, 83 percent were loaded.

According to the TSA, Hartsfield-Jackson Atlanta International Airport tops the list of firearms discoveries for 2016, with a total of 198 firearms. Dallas/Fort Worth International comes in at No. 2, with 192 firearms, followed up by George Bush Intercontinental Airport in Houston with 128. Phoenix Sky Harbor International, Denver International, Orlando International, Nashville International, Tampa International, Austin-Bergstrom International and Salt Lake City International also made the list.

The most recent “Week in Review” put out by the TSA covered the week of June 19 – June 25, just prior to Independence Day. That week, 59 firearms were found at TSA checkpoints across the U.S. as well as inert blasting caps (detonators), fireworks and knives.

None of these items are permitted in the secure area of the airport or inside the aircraft.